A rule of thumb used by pollsters that says incumbents rarely get a higher percentage in the election than they receive in polls, and that voters still undecided on the very last poll tend to “break” disproportionately for the challenger.

Michael Barone: “The assumption has been that voters know an incumbent, and any voter who is not for him will vote against him.”

Polling Report: “It seems that undecided voters are not literally undecided, not straddling the fence unable to make a choice – the traditional interpretation. An early decision to vote for the incumbent is easier because voters know incumbents best. It helps to think of undecided voters as undecided about the incumbent, as voters who question the incumbent’s performance in office. Most or all voters having trouble with this decision appear to end up deciding against the incumbent.”

Nonetheless, empirical data suggests the rule may be a myth. Nate Silver notes that it is “extremely common for an incumbent come back to win re-election while having less than 50 percent of the vote in early polls.” In addition, “there is no demonstrable tendency for challengers to pick up a larger share of the undecided vote than incumbents.”

The intricate knowledge of a process not normally known to the public and only of interest to insiders.

William Safire: “From its sports context comes its political or professional denotation: minutiae savored by the cognoscenti, delicious details, nuances discussed and dissected by aficionados. In politics, candidates who say they want to discuss larger issues look down their noses at the journalists and think-tankers who bedevil them with questions about campaign techniques, fund-raising plans and poll results. To them, inside baseball has a pejorative connotation that the phrase never gained in the baseball world.”

An impeachment is a formal charge of criminality raised against an elected official in the first step to remove them from office. In the federal government, only the House of Representatives may bring an impeachment while only the Senate may try and convict the accused. A conviction requires a two-thirds vote in the Senate and results in removal of the accused from office.

Impeachment can also occur at the state level, according to their respective state constitutions.

The impeachment process should not be confused with a recall election which is usually initiated by voters.